Punctile resurfacing has been developed for effective skin rejuvenation for the improvement of moderate wrinkles, scars, pores, pigmentation and skin texture. Pin point, segmental or fractional injuries to the epidermis can be delivered by needles.
For example, the MEDICAL ROLL CIT system, commercially available from VIVIDA SA of South Africa, employs a hand held roller with widely spaced micro-needles. The micro-needles only penetrate through the epidermis but do not remove or ablate it. This causes minute damages to the epidermis and percutaneous induces generation of collagen as a natural response to the wounds. After creating the micro-punctures in the epidermis, skin care substances are introduced by applying a lotion or cream over the wounded area. The active ingredients in the skin care substances pass through the micro-holes and thus are substantially more effective than topically applied drugs on the stratum corneum.
Another example is described in US Patent Application 20070073217 to James (published Mar. 29, 2007), which is a device for delivering a bioactive material to a subterranean layer of skin. The device has a roller head with needles that are operable to penetrate the stratum corneum. A bioactive material is disposed on one or more of the needles, whereby movement of the head operates to pick up the bioactive material and to deliver a portion of the bioactive material to a selected location, the selected location being a dermis, or an epidermis, or both the dermis and the epidermis. The bioactive material is, for example, a protein, a vitamin, a gene, a growth agent, a drug, and a peptide. The needles create an injury that triggers collagen production from one or more fibroblasts in the skin.
Multiple micro-needles have also been suggested for drug delivery, such as vaccines, through the skin. For example, U.S. Pat. No. 7,166,086 to Haider et al. (granted Jan. 23, 2007) describes a device for the delivery of a substance into skin via the rotational movement of a microabrader device. A substance is applied to the skin through the rotational movement of microprotrusions which may be imparted by a spring device present in the microabrader device or the motion of the operator through the handle of the microabrader device. The device can monitor its pressure against the skin. The delivered substance may be placed on the microprotrusions and a reconstituting liquid included in the microabrader device.
It is noted that Haider et al. distinguishes between different modes of delivering a drug through the stratum corneum, and this distinction is used in the description and claims of the present invention as well. The term “abrade” refers to removing at least a portion of the stratum corneum to increase the permeability of the skin without causing excessive skin irritation or compromising the skin's barrier to infectious agents. This is in contrast to “puncturing” which produces discrete holes through the stratum corneum with areas of undisrupted stratum corneum between the holes. The term “penetrating” refers to entering the stratum corneum without passing completely through the stratum corneum and entering into the adjacent layers. This is not to say that that the stratum corneum cannot be completely penetrated to reveal the interface of the underlying layer of the skin. “Piercing”, on the other hand, refers to passing through the stratum corneum completely and entering into the adjacent layers below the stratum corneum. It is noted that Haider et al. explicitly states that its device is for abrading the stratum corneum and not for puncturing.